If kissing counts as cheating most people including myself have cheated. Your only human, don't feel too bad. I know where you are coming from with feeling for your ex. I still care deeply for all my exes they were such important influences in my life and helped me become the man I am today. I let them go but I think sometimes I should have tried to get back together with some of them. As a guy I think I would have just asked for a date and if she agreed go on from there. If she wasn't interested I would have to respect her decision.
If you do get him bake their is a greater likely hood of repeating the same mistake have an honest conversation about this with him. If he truly cared for you and forgave you the breakup was inevitable the kiss was most likely just an excuse. take care learn and move on.
By the way sockz gave you the best idea of what is going on in your head. Understand that the human psyche is complicated and this experience should help you understand more about your self.
I think you're mistaking grief for love. They are linked in a way but the two aren't the same.
Love cannot thrive without the other person's affections; whereas grief only exists in the absence of someone you once loved. You can still feel attracted to someone, of course; but you can't love someone that you haven't been in a relationship with for a long time like that. At least not in the same way that you did before.
I know fairy tales would have us all believe that there's only one prince charming in the whole wide world that's right for us. But the truth is that you can fall in love with just about anyone. It's the relationship that's the hard part for most people.
If this guy doesn't want to be in a relationship with you then you just need to move on. This is your time to get some closure on the grief you've been experiencing for the last year. Once you put him behind you, you'll be able to smile again. The world will feel like you've just been born and you'll find someone more deserving of the love that you have to share.
He hurt you, so you used that as an excuse to cheat. The only person that provokes you to cheat is yourself. Someone else doing wrong doesn't make you change your morals, it makes you stick closer to them. So when it comes down to it, the reality is, you're a cheater and that's not his fault. He hurt you and that's not your fault. It's over. Time to move on. You're 'in love' with the memory of what once was. He's right, it wouldn't ever be the same again. You're missing something that cannot be.